The invention relates to an internal combustion engine or compressor having an actuator and more particularly to an adjusting apparatus and method for setting a lash between the actuator and a driven component such as a valve.
In a conventional engine a cam shaft drives a push rod, a rocker arm and in turn an intake or exhaust valve. To provide a compression braking system for such engines in the past has required adding additional components. For example, a housing having a fluid circuit therein is actuated by a solenoid. A control valve enables a flow of low pressure fluid to fill connecting passages and an actuator having a cavity and a master piston. The push rod actuates the master piston and with the control valve closed the slave piston is forced to open the exhaust valve during the preestablished cycle of braking. Thus, to adapt a conventional engine for use with the compression braking system has not been cost effective.
Additionally, when such component parts are initially installed and after use wear will occur. Thus, such component parts must be adapted to allow adjustment thereof. In present compression braking systems, an external adjusting screw is used to vary the relative position of the actuator to the exhaust valve.
In future applications, a camless engine is perceived and an actuator for the intake and exhaust valve can be hydraulically actuated. One such example is shown in U.S. Pat. No. 5,638,781 issued to Oded E. Sturman on Jun. 17, 1997. In Sturman""s patent a solenoid actuates a fluid control valve moving a spool into an open position. With the spool moved to the open position, hydraulic fluid acts on a stem of the valve and the valve moves off its seat into the open position. Lineal adjustment of the components before assembly or after operation of the engine and during working relationship of the engine fails to be shown or considered.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the invention an engine has a cylinder and has a piston therein. A pair of valves are operatively positioned relative to the piston. The pair of valves are actuated by a valve bridge. The valve bridge is actuated by a cam shaft and moves the valves between an open position and a closed position during an operating mode of the engine. The engine has a controller operatively attached thereto. An actuator is attached to the engine. The actuator is spaced from the pair of valves a predetermined distance and one of the pair of valves is movable between an open position and a closed position by the actuator independently of the actuation of the pair of valves being actuated by the valve bridge and the cam shaft.
In another aspect of the invention a method of adjusting a clearance between an actuator and an end of a valve is provided. The method has the steps of retaining a first end of the actuator in a fixed non-rotating position. Releasing a locking device. Rotating a second end of the actuator. And, tightening the locking device after the clearance has been adjusted.
In another aspect of the invention an actuator is provided. The actuator has a first end and a second end. The actuator is adapted for use in an engine to adjust a clearance between a valve having an end and the first end of the actuator. The actuator has a cylindrical member having a first end and a second end, and an inner diameter extending between the first end and the second end. A piston has a body portion defining an outer diameter positioned within the inner diameter of the cylindrical member. A stem portion defines a first end being attached to the body portion and a second end has a flat thereon. The stem portion has an outer diameter and a central bore having a stepped configuration. The central bore is positioned in the body portion and the stem portion. A portion of the central bore is threaded. A stem member has a first end portion defining a first end and has a flat thereon, and a second end portion defines a second end and has a threaded portion thereon. And, the stem member has a central portion being threaded. The stem member is at least partially positioned within the piston and the threaded central portion is threadedly engaged with the threaded portion of the central bore. A cover has a central bore defined therein being positioned about the outer diameter of the stem portion and is attached to the cylindrical member. The piston, the cylindrical member and the cover define a cavity therebetween. And, a locking device is threadedly attached to the threaded portion of the stem member.